1. Field of the Invention
The disclosure generally relates to an isolation circuit, and more particularly to an isolation circuit for improving its test performance.
2. Description of the Related Art
In a low-power system, inactive power domains are usually powered off, and therefore the power consumption of the system is reduced. For example, while a smartphone is performing a talk function, a power domain in which an LCD (Liquid Crystal Display) is located is temporarily powered off, and another power domain in which a communication module is located is continuously powered on, such that the power consumption of the smartphone is reduced.
An isolation cell is usually incorporated into the aforementioned low-power system, and it is configured to prevent the powered-on domains and the powered-off domains from interfering with each other. However, in specific applications, an isolation-signal input terminal of the isolation cell is tied to a predetermined voltage. Since the voltage at the isolation-signal input terminal is unchangeable, a system tester cannot determine whether the isolation cell is normal in all circumstances.
Accordingly, there is a need to design a flexible and high-performance isolation circuit of a test circuit for testing the isolation cell.